Graham Arnold has built an impressive pedigree in the A-Legaue. Photograph: Dean Lewins/AAP Image

Since leaving the national team set-up in 2010, Graham Arnold has played a pivotal role in raising the tactical standard of the A-League, while his Central Coast nursery has become something of a ‘finishing school’ for young, raw Australian talent. After being overlooked for the Socceroos job, it is now time for Arnold to move on to bigger and better things. It had to happen eventually.

Despite the recent success of the A-League in attracting crowds, sponsors and marquee players, it is an inescapable reality that it remains a small competition. The season is short, squads are still limited by salary and size, and there are just 10 teams. Japan, where Arnold is heading, is at least a decade ahead of us, with greater vision, a larger competition and a more efficient player development pathway. Far from a criticism, this is where we are at in our football development.

For decades, well before the advent of the A-League, we’ve been fretting about the ‘brain drain’ which has occurred as a consequence of the freer movement of labour across borders. It began, of course, with the players, and Graham Arnold was one of the pioneers. Now, we are witnessing a new drain of coaches, and Arnold is again leading the way.

It was always a matter of when and not if for Arnold. In June he created headlines by turning down a job a Sheffield United, labelling their football department “prehistoric”. The English wouldn’t have liked that. Who was this convict upstart rubbishing their football?

Arnold’s own attitude towards moving on from the A-League remains a healthy reference point. When Mustafa Amini transferred from the Central Coast to Borussia Dortmund, Arnold commented that it was an inevitable consequence of his talent, and reminded us that it is every player’s dream to move overseas. Likewise, when Tom Rogic was scouted by Celtic, he left with Arnold’s blessings and his support. Despite the trouble it caused him personally to have to rebuild his squad over and over again, Arnold has continually kept things in perspective.

Indeed, he speaks often about the fact that his success is measured by how many young players he can help move overseas, and how many millionaires he can help create. Arnold speaks with pride that “they are all very set and secure for their future life, which is fantastic". It’s an attitude which builds respect among his playing group, while also showing an understanding of where the A-League sits on the player development production line.

The reality is for every player that moves abroad, a space opens up for another to fill their role. Recent events suggest the same too has to be said for coaches. In the space of less than a month, Ange Postecoglou has been named Socceroos boss and Arnold is leaving for Japan. Their assistants, Kevin Muscat and Phil Moss, step in to fill the void. Win win.

In this case, Central Coast Mariners have again shown that they live by the motto ‘failing to plan is planning to fail’. They’re a tight-knit group in Gosford, and according to the Mariners group general manager Peter Turnbull, Arnold has been grooming Moss to take over for 18 months. Whether Moss can deliver the same results as Arnold remains to be seen, but everything has been done to make the transition as seamless as possible.

What Arnold does in Japan remains anyone’s guess. His challenges will be both cultural and football-related. Still, he has some experience in Japan from his time at Sanfrecce Hiroshima in the late 1990s, and Vegalta Sendai are known as a strong community club. If he can perform to expectations, don’t be surprised if a European move is next.

Twenty years ago, when Arnold was still a player, he was critical of the lack of respect and support for Australian coaches. Few Australian managers have come under as much criticism as him, especially during his time with the Socceroos in the Asian Cup in 2007 and the Olyroos in 2008.

However, as a club coach he has certainly proved his doubters wrong, leading the Mariners to a minor premiership, a championship and qualification to the Asian Champions League. Like all Australians who work in creative fields, Arnold must leave to continue his career and better his own craft. There is little left for him to do here.